1. Field of the Invention
The present invention relates to a photosensitive material processing apparatus and a method using the same. The photosensitive material processing apparatus includes a conveyance roller pair near an insertion opening thereof. When an operator inserts a photosensitive material through the insertion opening until it is nipped by the conveyance roller pair, the photosensitive material processing apparatus processes the photosensitive material at a predetermined conveyance speed.
2. Description of the Related Art
The photosensitive material processing apparatus generally has a tray for manual feeding of a photosensitive material at the insertion opening thereof. When the operator places a photosensitive material on the tray and inserts the photosensitive material manually into the insertion opening, the conveyance roller pair that is provided near the insertion opening nips the material.
The conveyance roller pair is rotated at a predetermined conveyance line speed. After nipped by the roller pair, the photosensitive material is automatically conveyed to a processing section with processing solution and then to a drying section.
As the process advances, the processing capacity of the processing solutions such as developer and fixing solution is lowered according to the amount of the photosensitive material which has been processed (which amount will be referred to as xe2x80x9cthe process amountxe2x80x9d hereinafter). Therefore, in order to maintain the processing capacity at the satisfactory level, a replenisher needs to be added regularly.
The amount of the replenisher to be added is conventionally computed based on detection results of sensors, which are provided in the upstream of the conveyance roller pair at the insertion opening for detecting the photosensitive material. When the operator inserts the photosensitive material manually into the insertion opening, the sensors first detect the leading end of it. As the photosensitive material is conveyed by the conveyance roller pair, the sensors then detect the trailing end of the photosensitive material. The length of the photosensitive material in the conveyance direction thereof is obtained by multiplying the time during which the sensors are detecting the photosensitive material (xe2x80x9cdetecting timexe2x80x9d) by the conveyance line speed of the conveyance roller pair.
Further, conventionally, a plurality of sensors is disposed on a line along the width direction of the photosensitive material. The width of the photosensitive material is obtained based on the number of the sensors that detect the photosensitive material.
The process amount of the photosensitive material is determined as the area of the photosensitive material which has been processed. The area of the photosensitive material is obtained by multiplying the dimensions of the photosensitive material in the conveyance direction and the width direction thereof. In the replenishing system, the obtained areas are added one by one, and when the sum of the areas has exceeded a predetermined value, a certain amount of the replenisher is replenished. As a result, the processing capacity of the processing solutions can constantly be maintained at the satisfactory level.
However, there is a problem that the aforementioned detection time, which is used for calculating the area of the photosensitive material, may not be accurate. As there is a certain distance between the positions at which the sensors are disposed and the position at which the conveyance roller pair nips the photosensitive material, the time required for the photosensitive material to travel this distance is directly influenced by the speed at which the operator inserts the photosensitive material. In other words, the time required for the material to travel this certain distance is inevitably inaccurate and thus must be corrected.
The degree of error in the detection time may not be so significant unless the operator inserts a large number of photosensitive materials. However, when the intervals between each replenishing event is relatively long, the errors in the detection time are accumulated to a significant level. Eventually, there may result in a situation in which the processing solutions are not replenished by an appropriate amount.
In view of the aforementioned facts, an object of the present invention is to provide a photosensitive material processing apparatus that corrects the errors in the detecting time of the sensors due to the difference in the insertion state of the photosensitive material caused by manual insertion by the operator, and accurately obtains the process area of the photosensitive material required for calculating the amount of the replenisher to be replenished.
A first aspect of the present invention is a photosensitive material processing apparatus including a conveyance roller pair disposed near an insertion opening, which nips the leading end of a photosensitive material, and transports the photosensitive material at a predetermined conveyance speed (VR) when the photosensitive material is inserted until it is nipped by the conveyance roller pair, the photosensitive material processing apparatus comprising: (a) a plurality of sensors for detecting the photosensitive material, the sensors being disposed in the upstream of the conveyance roller pair along the width direction of the photosensitive material and being divided into at least two groups that are offset from each other in the conveyance direction of the photosensitive material; (b) process area computing means for computing a process area of the photosensitive material based on the detection results of the sensors; and (c) correcting means for correcting a photosensitive material detecting time (X) during which the photosensitive material has been detected by a reference sensor group by using detecting time difference (xcex94t) between sensors that are offset, and thus correcting an error in computation by the process area computing means, the errors being caused by variance in insertion time during which the photosensitive material is conveyed from the sensors to the conveyance roller pair.
According to the first aspect, the offset state of the sensors results in detecting time difference (xcex94t) between the offset sensors when the photosensitive material is inserted. An insertion speed (VH) of the photosensitive material is obtained from the detecting time difference (xcex94t) and the offset distance (LOS). An insertion time is computed based on the insertion speed (VH) and the known insertion distance (LIN) from the sensors to the conveyance roller pair. Thereafter, the process area of the photosensitive material is obtained accurately by eliminating the effect of the difference in the insertion time and computing the accurate process area by the process area computing means.
A second aspect of the present invention is a photosensitive material processing apparatus including a conveyance roller pair disposed near an insertion opening, which nips the leading end of a photosensitive material, and transports the photosensitive material at a predetermined conveyance speed (VR) when the photosensitive material is inserted until it is nipped by the conveyance roller pair, the photosensitive material processing apparatus comprising: (a) a plurality of sensors for detecting the photosensitive material, the sensors being disposed in the upstream of the conveyance roller pair along the width direction of the photosensitive material, being able to detect photosensitive materials having different sizes in the width direction thereof, and being divided into at least two groups that are offset from each other in the conveyance direction of the photosensitive material; (b) storing means for storing in advance an offset distance (LOS) between a first sensor group and a second sensor group adjacent thereto in the conveyance direction, and a conveyance distance (LIN) between a reference sensor group as one of the sensor groups and the position at which the conveyance roller pair nips the photosensitive material; (c) insertion time computing means for computing an insertion speed (VH) of the photosensitive material from a detecting time difference (xcex94t) between the detecting time of the first sensor group and the detecting time of the second sensor group, and an offset distance (LOS) between the first and second sensor groups, and then computing an insertion time required for the photosensitive material to be conveyed at the insertion speed (VH) by the conveyance distance (LIN); (d) means for computing the length (L) of the photosensitive material in the conveyance direction thereof by multiplying the time, that is obtained by subtracting the insertion time (LIN/VH) from the detecting time (X) during which the photosensitive material has been detected by the reference sensor group, by the conveyance speed of the conveyance roller pair (VR) and then adding thereto the conveyance distance (LIN); (e) means for determining the length (W) of the photosensitive material in the width direction thereof based on the detection results of the plurality of sensors; and (f) process area computing means for computing the process area (S) of the photosensitive material from the computed length (L) of the photosensitive material in the conveyance direction thereof and the determined length (W) of the photosensitive material in the width direction thereof.
Photosensitive materials of many widths may be used in the present invention. In the second aspect, the sensors are disposed or selected so that at least two sensors that are offset in the conveyance direction of the photosensitive material correspond with each width of the photosensitive material. For example, when the photosensitive material is inserted in a left- or right-end-aligned manner, it suffices to provide or select a sensor located at the reference end and a sensor adjacent (in the width direction of the photosensitive material) thereto. When the photosensitive material is inserted in a center-aligned (centering) manner, it suffices to provide or select a sensor located at the central position and a sensor adjacent (in the width direction of the photosensitive material) thereto.
The disposed or selected two (groups of) sensors are offset from each other by the predetermined offset distance (LOS). The offset distance (LOS) and a conveyance distance (LIN), from a reference detecting position of on the most downstream-side groups to the position at which the conveyance roller pair nips the photosensitive material, are stored in advance (in storing means).
When the photosensitive material is inserted manually, the insertion speed may differ for each operator and may even differ each time at the same operator. The insertion time computing means computes the insertion speed (VH) from the offset distance (LOS) between the sensors and the detecting time difference (xcex94t) of the sensors that have been offset. Further, the insertion time computing means computes the insertion time (LIN/VH) that is the time required for the photosensitive material to be conveyed at the insertion speed (VH) by the conveyance distance (LIN).
Next, the means for computing the size of the photosensitive material in the conveyance direction thereof obtains an accurate length (L) of the photosensitive material in the conveyance direction by multiplying the time that is obtained by subtracting the insertion time (LIN/VH) from the detecting time (X) during which the photosensitive material has been detected by the sensors disposed at reference positions, by the line speed (VR) of the conveyance roller pair, and then adding thereto the conveyance distance (LIN) stored in the storing means.
The width (W) of the photosensitive material is determined based on the detection results of the sensors (by a means for determining the width of the photosensitive material). The process area (S) of the photosensitive material is computed accurately using the width (W) of the photosensitive material by a process area computing means.
Thus, the size of the photosensitive material in the conveyance direction thereof is accurately determined by eliminating the effect of the changeable conveyance time during which the photosensitive material is conveyed from the most downstream-side sensors to the conveyance roller pair, regardless of the difference in the insertion speed for each manual insertion event.